To sum things up: Super Resolution is real. If you have just one image containing a few pixels there is little you can do. But if you have a lot of slightly different and under-sampled versions of those pixels, then you can significantly increase the resolution of your images! For planetary astrophotography this is hardly ever the case however. Sometimes drizzling can give sharper results for low focal length recordings: when imaging the Sun in good seeing conditions at low magnifications for example. For short exposures of deepsky targets at lower focal lengths there is a much bigger chance it will actually increase the effective resolution. For most planetary recordings there simply is little to gain by drizzling.